1. Field of the Invention
The present invention is generally concerned with tools for tightening and then cutting clamps, for example the flexible strip of a tie clamp looped around one or more objects.
Two types of tool are currently available for this purpose.
The first type covers tools comprising two handles pivoted to each other and operating against elastic return means, comprising a first handle hereinafter referred to for convenience only as the tightening handle which has at its end grasping means adapted to grasp the clamp to be cut and a second handle hereinafter referred to for convenience only as the cutting handle which has at its end a cutter movable against elastic return means, with actuator means adapted to exert thrust on said cutter.
A tightening and cutting tool of this kind is described for example in French Pat. No. 2 400 995 filed June 2, 1977 under application No. 77 16827.
In this patent the actuator means adapted to exert thrust on the cutter are controled by a specific lever pivoted to the cutting handle for operation by the user.
This arrangement is satisfactory and advantageously results in relatively simple and economical forms of construction.
It does leave the choice of the moment to make the cut up to the user, however.
Thus cutting is done independently of the tensioning of the clamp to be cut.
If this tension, on which ultimately depends the clamping action of the clamp on the object or objects that it surrounds, is insufficient, then the clamping may be inadequate.
The second type of tightening and cutting tool for clamps currently available covers tools comprising a plate with one end which forms a fixed handle used to manipulate the assembly and, facing this fixed handle, a movable handle which is pivoted to the plate and which controls a tightening and cutting mechanism supported by the plate.
A tool of this kind is described for example in U.S. Pat. No. 4,081,002 granted Mar. 28, 1978.
It has the advantage of utilising a detent mechanism, that is to say a sudden release mechanism, systematically making the cut immediately when the tension on the clamp to be cut reaches a predetermined value.
The corresponding forms of construction are relatively complex, however, and therefore costly.
A general object of the present invention is a tool for tightening and cutting clamps that is free of these disadvantages and offers other advantages.